'Toxic sugar bait' to help control malaria

Melon and guava extracts, as well as extracts from beer and boric acid, can help people in arid and semi-arid regions to control mosquito populations, according to a recent Israeli study.

Relying on the fact that some breeds of mosquitoes get some essential nutrients from fruit sugars, the researchers made cocktails of easily-available substances (called attractive toxic sugar bait, or ATSB) that acted as natural mosquito traps.

The bait can be sprayed onto patches of vegetation, such as where trees are flowering.

In order to test the ATSB method, the research team tested the method on a population of mosquitoes living in a sugar-rich Israeli oasis.

The oasis was located in the Arava Valley desert, which the study authors maintain has been uninhabited for 40 years.

There was a small fresh-water spring, and a dense area of vegetation at the centre of the oasis, covering about five hectares.

They found that giving mosquitoes free rein to get nutrients they needed from sugar gave them a much higher reproductive capacity, drastically increasing the chances of transmitting malaria.

At the site where the researchers tested ATSB, the mosquitoes barely managed to live for long enough to transmit the disease.

Using ATSB to limit sugar intake also limited female lifespans, eventually limiting the capacity of the mothers' eggs to mature at all.

Yosef Schlein, a professor at the Kuvin Centre for the Study of Infectious and Tropical Diseases at Hebrew University in Israel said people had known for a long time that mosquitoes needed sugar meals in order to survive.

He said no-one until now had considered damaging mosquito populations by placing limits on sugar, however.

When a research team in Mali tested ATSB, they were able to wipe out a mosquito population almost entirely, using a combination of honey, melon, guava, boric acid, beer, and water.

Mahamoudou Toure, a researcher at the Malaria Research and Training Centre at the University of Bamako in Mali, who co-authored the Malian study testing ATSB, said that researchers needed to ensure that the method did not kill other insects in the region.